I too use or at least hear and know  "grin like a Cheshire cat" and
"carrying coals to Newcastle."  However, I would not use it in the same way
as Gordon says--taking flowers to someone who has a big flower garden is
like carrying coals to Newcastle,  maybe taking a copy of a memo to the
person who wrote it would be like carrying coals to Newcastle.  I think you
need to include the act of bring something somewhere before you use the
term.
I have never even heard of fighting like a Kilkenny cat.  And I don't
Gordon's meaning of "something that won't keep" here in Washington state
either.  Soft drinks are pop here or used to be before we had such an influx
of people from other parts of the country!
One of my favorite ones from the South that I just learned in the last two
years is "that dog won't hunt" meaning something like that is an idea that
you won't get people to believe--that bird won't fly!

> ----------
> From:         GORDON RIVES CARMICHAEL[SMTP:[log in to unmask]]
> Reply To:     Assembly for the Teaching of English Grammar
> Sent:         Tuesday, December 29, 1998 7:29 AM
> To:   [log in to unmask]
> Subject:      Re: Idioms using cats
>
> <<Message: Microsoft Exchange Message>>
>     Hello, again, Ito,
>         I cannot answer for every English speaker, but I often hear "grin
> like a
> Cheshire cat" - perhaps because of the continuing popularity of Alice's
> Adventures in Wonderland. It clearly shows a slightly wicked or knowing
> smile -
> someone who knows a secret or has done something clever or sneaky ("act
> like the
> cat who ate the canary"). I do not hear "fight like Kilkenny cats"
> anymore, but,
> rather, "fight like cats and dogs." However, "carrying coals to Newcastle"
> is
> still viable as a demonstrative idiom - it means doing something
> unnecessary or
> redundant. ("Printing every e-Mail on hard copy is like carrying coals to
> Newcastle.")
>       Ito, you have already learned that idioms are used throughout
> English.
> However, you may not have yet discovered that different English speaking
> areas
> may use different idioms, or there may be 'regional' idioms that have
> little or
> no meaning outside of that area. This is similar to many words or terms
> for
> things, which are regionally labelled. For example, in different parts of
> the
> United States, "soft drinks" [as we call them in Texas] (Pepsi, Coca Cola,
> Royal
> Crown, root beer, cream soda ) are called different things = "pop,"
> "cola,"
> "soda," "soda pop," "fizz," and probably several others I do not know.  An
> idiom
> used in Texas, where I live, may be unknown in California. An example of
> this is
> "something that won't keep," meaning something very special or
> ostentatious =
> "She has a diamond ring that won't keep." My friends here in Texas
> understand
> this idiom, but my friends in California were unsure of its meaning.
>     You have tackled one of English's most difficult areas "to pin down,"
> - to
> find unambiguous definitions. I hope this helps in some small way. If not,
> you
> may want to contact me directly at  [log in to unmask] Best wishes.
> Gordon
> Carmichael
>
> Ito kazumasa wrote:
>
> > Hello listers,
> >
> > >Kazumasa-san, I am not sure exactly what >your question is.
> >
> >  Thank you very much Mr.Medley and Mr.Carmichael for your prompt
> replies.
> > And I am sorry that my query was unclear. I'm going to make myself
> clearer
> > now.
> >  Are the two idioms("grin like a Cheshire cat" and "fight like Kilkenny
> > cats" ) used in speech or in writing frequently? Or are they heading
> toward
> > extinction as the case of "carry coals to New Castle"? (Since New Castle
> is
> > no longer a prosperous mining town, and few homes use coal for heating
> > nowadays, this idiomatic expression is on the verge of extinction) I
> > resorted to many dictionaries and even did a research on AltaVista, but
> I
> > found no evidence that shows that these two idioms are being used by
> English
> > native speakers now.(AltaVista gave me wonderful anecdotes about their
> > origins, though)
> >  In the movie "Batman Returns", the idom "Curiosity killed the cat" was
> used
> > in an altered form(What did curiosity did to the cat?) and the Cat Woman
> > says "A cat has nine lives, you know." while fighting with a
> cold-blooded
> > entrepreneur. I think this means that the two idioms are in wide use
> among
> > English natives. However, I haven't seen any movie in which these are
> > actually used.
> >   So, my question is, do you use "grin like a Cheshire cat" and "fight
> like
> > Kilkenny cats" often? I would appreciate it if you would provide me any
> > feedback on this query.
> > Thank you very much in advance.
> >
> > Kazumasa Ito
> > Sapporo, Japan
> > [log in to unmask]
>